<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <ul id="ul">
        <li>语文</li>
        <li id="li">数学</li>
        <li>英语</li>
        <li>历史</li>
        <li>政治</li>
    </ul>


    <script src="./three1.js"></script>
    <script src="./three2.js"></script>
    <script src="./three3.js"></script>
    <script src="./three4.js"></script>
    <script>
        // let li=document.getElementById('li')

        // setTimeout(() => {
        //     li.innerHTML='历史'
        // }, 2000);

        let li=document.getElementById('li')
        setTimeout(() => {
            li.textContent='<a href="#">历史</a>'
        }, 1000);
    </script>
</body>
</html>